September 15, 2008

YICHANG, Sept. 13 (Xinhua) -- Chinese experts said Friday that although the Yangtze River was still at flood season, the plan to raise the water level of the Three Gorges Project water to 175 meters in mid-September would not pose any flood control harm.

No exact date was given for starting to do so, which is still awaiting approval from the State Council, the country's Cabinet. This broader timetable, however, is about half a month earlier than the original plan.

Yuan Jie, chief of Three Gorges Project Tiered Control Center, said the rescheduled plan for water level rise would help the project realize its full potential.

He said there was no need to worry about flood control safety as historical data prove it is unlikely to have major flood peaks on the upper reaches of the Yangtze after mid-September.

Dams built on the Yangtze's upper reaches in recent years mean that water flow in the flood season is now less than before.

Yuan's opinion favoring the rescheduled plan was echoed by Chen Lei, deputy chief engineer with the Three Gorges Project Representative Bureau of the Yangtze River Water Resources Committee.

"The exact date and ways for raising the level will be decided by conditions on the upper reaches of the river and flood control conditions on the lower reaches. In addition, we have to get approval from the State Council," said Chen.

"To raise the water level from 145 meters at present to 175 meters, we need an extra 22.1 billion cubic meters of water, more than double the volume of water needed to drive up the water level from 135 meters to 156 meters in 2006 which was done in 37 days," said Chen.

The monitored water level was 145.84 meters as of 10 a.m. Wednesday, said a source with China Three Gorges Project Corporation (CTGPC).

Cao Guangjing, deputy general manager of CTGPC, said the plan to raise the water level of the Three Gorges reservoir to 175 meters wouldn't cause massive silting, or lead to serious natural disasters in nearby areas.

Silt into the Three Gorges Reservoir has been on decline in recent years thanks to factors including construction of some 100 hydropower stations and the efforts to grow trees on farmland.

Statistics show that 210 million tonnes of silt has been washed down into the Three Gorges Reservoir each year since 2003 when the water level was raised to 135 meters, far below the expected 530 million tonnes a year. Less than 100 million tonnes of silt has been swept into the reservoir this year ending mid-August.

"We have taken measures such as relocating residents living on dangerous grounds and improving monitoring to get information first over the past years, so we are confident that occurrence of major geological disasters causing heavy fatalities will be reduced enormously," said Cao.

There have been cases of landslides and minor earthquakes around the Three Gorges Reservoir Area after the water level was raised to 135 meters in 2003 for the first time. It is not clear whether Cao was referring to this.

Cao admitted water bloom made a frequent presence in the Three Gorges Reservoir since 2003 when the water level was raised to 135 meters high.

He promised to cooperate more with Chinese scientists and get experience in harnessing the environmental problem on the massive reservoir by carrying out an experiment on Xiangxi Creek, a minor tributary of the the Yangtze.

The Three Gorges Project, launched in 1993 with a budget equivalent to 22.5 billion U.S. dollars, is a multi-functional water control system built at the upper middle reaches of the country's longest river.

Its main works are a dam, a five-tier ship lock, as well as the installation of 26 hydropower turbo-generators. Its key functions include flood control and power generation.

The project has been constructed in three phases and storing water at the 175 meter level is a requirement for the last phase of construction.

Altogether 1.24 million residents in Chongqing and Hubei Province were relocated to make way for construction of the project as of June.

The Three Gorges called for the 26 generators, 14 on the left bank and 12 on the right, to produce 84.7 billion kwh of electricity annually upon its completion.

It will expand further to include six more turbines by 2012.

The 26 planned power generation turbines will be completed in November as the installation of the last one nears the end, the project developers said on Monday.